


Undertale Prompts

by Sharkdukes



Series: Undertale Prompts [1]
Category: Undertale (Video Game)
Genre: Affectionate Sans, Bone Cracking, Courtship Habits, Cuddly Sans, Dominant Reader, Dominant Sans, F/M, Flustered Sans, Monster Heat Cycles, Other Additional Tags to Be Added, Smug Reader, Smut, monster reader, submissive sans
Language: English
Status: Completed
Published: 2016-07-21
Updated: 2016-07-27
Packaged: 2018-07-25 22:09:57
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 11
Words: 12,276
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7549177
Author URL: https://archiveofourown.org/users/Sharkdukes/pseuds/Sharkdukes
Summary: <blockquote class="userstuff">
              <p>A prompt fic.</p><p>I think most of you know how these work.</p><p>Send me a request and I may just write it.</p><p>I will add tags as I write.</p><p>EDIT: Asks are now closed for this fic!</p><p>I wanna thank everyone who submitted a request, even if I didn't get around to it. I'll probably do another one of these sometime in the future, but for now, I'll be focusing on the other stories I'll be writing.</p>
            </blockquote>





	1. An Introduction

**Author's Note:**

> Decided that I'm definitely doing the prompt fic.

Hello to you all!

 

So, I've decided that I'm definitely doing the prompt fic. As stated in the notes above.

 

Feel free to send me prompt ideas via the comments. I'd love to hear the suggestions you have.

 

Also, please note that there are some things that I will absolutely _not_ write about.

 

So if I were to get a request like that, I would have to politely say no to whomever asked.

 

Yeah, so. that's all I have to say on the matter.

 

Ask away!


	2. Heat Cycle

**Summary for the Chapter:**

> SansIsVertabae wanted some Sans in heat x Reader.

**Notes for the Chapter:**

> This is my first smut (that I'll be posting) so I don't know how good it'll turn out.

You thought of the events that had led to your current predicament.

 

That being that you were pinned underneath your boyfriend who was breathing as if he had just run a marathon.

 

Which was an impossible feat seeing as how Sans was the laziest man you had ever met.

 

The two of you had been dating almost a year now with little to no bumps in our relationship. You had monsters being able to sense emotions wafting off of souls to thank for that.

 

You spent time with Sans almost everyday, save for when you had to cram for exams or were busy with work.

 

You had previously been under the impression that you had an exam today. However, due to the professor failing to make enough copies as well as an answer key, the exam had been postponed to next Tuesday.

 

That meant you could spend the rest of the day with your Sansy-pansy!

 

He acts like he hates that nickname but you've seen the smile he cracks and the blush that spreads whenever you call him that!

 

Papyrus' - Sans' younger brother whom you think is the most precious cinnamon roll to have ever been baked - car wasn't in the driveway. He was probably over at Undyne's for training. He was the more active one of the two brothers.

 

Sans had given you a key to his house months ago after you showed up for date night and he had fallen asleep, leaving you locked outside.

 

He spent a good portion of the date trying to get you out of your bad mood. It had been raining damn it!

 

Anywho, you let yourself in and locked the door.

 

"Sans! The exam was cancelled! That means we can spend the rest of the day cuddling and criticizing Mettaton's terrible movies!"

 

No response. That's strange. Usually your silly skelly would have been on you the moment you walked through the door, showering you with kisses and bad pick-up lines.

 

You checked the first floor of the house. He obviously wasn't in the living room. Not in the kitchen either. You checked the hall closet just to make sure he wasn't trying to spook you. Nada.

 

You headed upstairs. Sans was probably in his room asleep. Despite Papyrus' constant insistence that Sans would always slack at work, that couldn't be farther from the truth. Sure, Sans was lazy. But when he was invested in something he gave it his all. Your poor baby was working himself down to the bone!

 

...Okay, pun not intended, but that was pretty funny.

 

You headed upstairs and made a right. You stopped at Sans' rooms' shut door. He always kept it shut to keep Papyrus from seeing how messy he kept it. It had been so much worse when you had started dating, but it had gotten better. You were happy to say that the sock pile and trash tornado - however the _Hell_ that worked - were gone.

 

You placed your hand on the doorknob and were about to enter when you heard a soft grunt. You placed your ear on the door.

 

You heard low grunts and panting coming from inside. Was Sans-

 

Was Sans having another nightmare?

 

You'd slept over a few times, so you knew that those could get pretty bad. Prepared to dodge whatever might be being thrown about by magic, you yanked open the door to see- Oh.

 

You felt your face heat up. Well. At least he wasn't having a nightmare like you thought.

 

Sans was laid back on his bed. One hand up his shirt fondling his ribs, the other was fisted around an impressive glowing, blue erection. Sans' face was flushed, his ribcage rising up and down with his panting.

 

"F-Fuuuuck!"

 

Blue semen splurted onto Sans' hand, his bedsheets, and his lower ribs. His breathing slowed for a moment and he opened his eyes.

 

His right eye was devoid of its pupil, the left was a brilliant cerulean blue. Residual magic seemed to waft out in a smoky haze from it. Sans turned his head.

 

And locked eyes with you.

 

You felt more blood rush to your face.

 

"Uh... Hi Baby..."

 

Eloquent as ever . Here, allow your mental audience to applaud. Slow and condescendingly.

 

"I'll just, um, be downstairs."

 

You turned to go, but the door shut and locked itself.

 

You turned your gaze back to Sans who had come up behind you- Hi yes hello he's very close to you now.

 

He had a heated look in his eye, almost predatory. His breathing was still labored. He raked his eye up and down your body.

 

You're beginning to regret wearing that spaghetti-strap tank top and tight jeans right now.

 

Sans grabbed your shoulders and pinned you to the door.

 

Okay. So that was how you got where you currently are.

 

Sans leaned down and licked the side of your neck before placing kisses up and down it. You shivered.

 

He pulled back.

 

"Hey, Kitten. What're you doing home so early?"

 

You stammered out that the exam had been cancelled and came over to see if he wanted to hang out.

 

"B-but I see that you're busy right now! I'll just come back another time!"

 

You tried to get out of Sans' grip but he just tightened it.

 

Ow, that actually hurt a bit.

 

"What's the rush, Sugar? You just got here. C'mon and sit down."

 

He took your hands and sat you down on the bed. He had tucked his erection into his shorts, but you could see the faint glowing outline of his bulge.

 

Sans raked his eyes over you once more. God you were utterly gorgeous! He had no idea how a guy like him managed to got a lady like you to go out with him, but he was glad you were his and no one else's.

 

Sans leaned in and sniffed your hair. Okay, that was moving back into somewhat familiar territory. Sans would sometimes do that when you two were snuggled up on the couch. You had no idea why and he didn't offer an explanation. He kissed your cheek, then your lips. It started out innocent enough. Light pecking here and there with the occasional nibble. Then things got hot and heavy.

 

You felt something wet and slick swipe at your lips. You gasped in shock and tried to pull back. But Sans took the opportunity to shove his tongue into your mouth. There wasn't much of a fight for dominance. Sans was really skilled at this. His tongue explored every recess of your mouth. He only broke the kiss because air was a thing you both needed.

 

You were about to ask Sans what had gotten into him when it hit you. Or rather, the smell did. It was musky and all over the room and coming from Sans. That, added with his dominant behavior and the surge of affection led to one conclusion.

 

"Sans? Are you... In heat?"

 

Sans stopped nuzzling the side of your head and froze.

 

"How did you-"

 

"Papyrus. He said you get like this once a year and leaves you to your own devices. Oh! So that's why his car wasn't in the driveway!"

 

Sans was mortified momentarily over the fact that his baby brother knew what a heat was and apparently had for some time. But that feeling faded fast when you placed a hand on his femur.

 

_If you would just move your hand up a bit higher-!_

 

"Do you... Want me to help you with it?"

 

Sex wasn't a topic you were unfamiliar with. You knew what went on, but had never had it. You usually satisfied yourself with toys or your fingers and porn.

 

Honestly speaking you should've been a bit more embarrassed about asking such a thing. But this was Sans you were talking about.

 

You loved him. And he knew it.

 

Sans audibly swallowed.

 

"You sure Babycakes?"

 

Boy he sure was fond of nicknames today. Not that you minded.

 

"Yeah. I love you and I don't want you to be miserable for however long this lasts. Just, be gentle, okay?"

 

He nods and pushes you back onto the bed.

 

"Uh, wait. Clothes. Clothes are a thing. We should probably get them off."

 

Sans sits back up and starts hastily removing his T-shirt and shorts. You had gotten your shirt and pants off before Sans put his hands on yours.

 

"Let- Let me take 'em off. Please?"

 

You simply nodded and he took over. You could feel his hands shaking as he took off your bra. Wow, he must really be holding back. You _did_ tell him to be gentle...

 

Once your bra was off, Sans stared at your bare chest. You were becoming embarrassed and attempted to cover them, but Sans gripped your hands and pinned you to the bed again.

 

" _Don't hide yourself from me,_ " he growled out.

 

That sent a surge of heat to your core. You could feel your panties getting even more damp then they already were at Sans' show of dominance. He inhaled briefly and chuckled.

 

"I can smell how aroused you are." He grabbed a breast and began kneading it. His other hand began rubbing you beneath your panties.

 

"Ah~!"

 

It was one thing when you touched yourself, but it was something else entirely when someone else was doing it. Sans pinched a nipple between his phalanges. He circled the other with his tongue before licking and nipping at it. He then started suckling on it.

 

"Saa-aaans! Hah, ah... Ah!"

 

Sans had increased the pace of his fingers running against your pussy. He could feel you soaking your underwear and it was turning him on even more than he already was. His erection throbbed almost painfully at the reactions he was getting from you. He decided that you'd had enough teasing a nearly ripped your panties off.

 

"Mmmmph. Just _look a_ t yourself, Babygirl. All hot and bothered from just a little bit of teasing. And look, your cunt's _soaking._ 's that for me? You are just the sweetest. I bet you taste sweet, too..."

 

He didn't give you time to respond. Sans traced his tongue up your throbbing mound. You moaned at the contact and practically screamed when he began tongue fucking you.

 

"Gah~! Sans- I- I can't-"

 

Sans only increased his pace. He loved hearing you come undone. It was his new favorite sound.

 

You came hard and fast on Sans' tongue. He eagerly lapped up your juices before grabbing ahold of your thighs.

 

You were a bit concerned. Sans was average in length but had a bit of girth on him. You hoped he would fit. He leaned over you and nuzzled your cheek.

 

"Don't worry, Babe. I won't hurt you."

 

Sans lined himself up with your entrance and began pushing in slowly. It burned unpleasantly. It was when he met some resistance and broke through that it really started to hurt. 

 

"Sans, please! It hurts-!"

 

You were crying a little bit and whimpering. Though he'd like nothing more than to pound mercilessly into you until you couldn't remember anything but his name, Sans steeled his resolve. This was your first time. He did his best to console you.

 

"Shh shh shh. You're doing so good, Baby. So good. I'm almost all the way in. God you're so warm and wet and _oh so fucking tight._ "

 

Sans finally stopped moving and gave you time to adjust to his size. There was almost nothing he hated more than seeing his baby in pain.

 

After a few minutes, the pulsating pain dialed down to a dull throb. You nodded at Sans to start moving. He brought his hips back, stayed about halfway in you, the moved back in. The pain receded and all that was left was the indescribable pleasure that you felt.

 

"You can- Aaaaahnnn~! You can move a little faster."

 

Sans did just that. The way you clenched around him and the sounds you were making made his cock pulse with want and need. He wanted to spill his seed inside you. Fill you up until you couldn't hold anymore. The thought of his cum seeping out of you nearly made him lose it.

 

The pace increased. You begged Sans to go just a little bit harder. He lifted one of your legs over his scapula. He could pound into you so much deeper from this angle!

 

You could hardly form coherent sentences as it was. Then Sans hit that magic spot in you and you. Just. Lost. It.

 

You threw back your head and let out a keening moan. You clenched around Sans as you felt the coil of pleasure in you finally snap.

 

When your cunt clamped down on his cock, Sans felt himself finish inside you. His hips jerked erratically as he came.

 

After a few minutes of the two of you catching your breath, Sans slid out of you, along with a bit of his cum.

 

_Fucking hot._

 

Sans drew the covers over the two of you.

 

"Just so you know. I'll be ready to go again here in about an hour or so. Still feel up to helping me out Babydoll?"

 

You snuggled up close to your boyfriend. That was the most pleasurable thing you'd ever felt. And according to your friends, sex only got better the more you practiced.

 

You relayed that little nugget of information to Sans. He chuckled.

 

"Well then," he smooched you and you could taste yourself a little bit, "I guess we'll just have to practice until we're perfect at it."

 

Sans' heat went on well into the following week. Luckily, you'd gotten a bit of time away from your horny boyfriend to study a bit more for that exam, not that it mattered seeing as how you knew the subject like the back of your hand. Sans had made sure his disapproval of you leaving the bed that day was known. He clung to you like some affection starved cat. He even hissed at you when you made a move for the front door!

 

All was forgiven when you came back and gave in to his sexual desires.

 

You were really glad your professor had forgotten to make an answer key and the right amount of exam copies for everyone.

 

It brought you and your boyfriend closer than you were before.

 

**Notes for the Chapter:**

> I will just leave this here.
> 
> Also, how do I upload Gifs?


	3. Pick-Up Lines

**Summary for the Chapter:**

> BBBlue requested some Sans going overboard with pick-up lines.
> 
> I'm happy to oblige.
> 
> (Also, I have NOT seen the Rocky Horror Picture Show, but I have heard of it. It's on my To-Do list of things to watch.)

**Notes for the Chapter:**

> Fluffy chapter ahoy!

12:58 P.M.

 

You and Sans were just hanging around in the living room of his house when it started.

 

"Does your left eye hurt? Because you been looking right all day."

 

You glance over at Sans.

 

"What?"

 

He just waggles his bonebrows at you.

 

Help, something's wrong with my eyes - I just can't take them off you!"

 

Oh no.

 

"Have you been looking up terrible pick-up lines on the internet again?"

 

He just gives you this smug grin.

 

Uh oh. Prepare for the onslaught.

 

1:17 P.M.

 

"Baby, if you were a fruit you'd be a fineapple."

 

You put down the pineapple slices you'd gotten from the kitchen.

 

1:28 P.M.

 

"Your name must be Coca Cola, because you're so-da-licious."

 

You put the soda can back into the fridge. This was starting to get annoying.

 

2:45 P.M.

 

You'd locked yourself in the bathroom after the last horrible pick-up line.

 

Really Sans? _'Did you sit in a pile of sugar? Cause you have a pretty sweet ass.'_ Really?

 

You honestly thought that most of them were pretty hilarious, but that wasn't why you locked yourself in the bathroom.

 

You were embarrassed.

 

You'd had this - pardon the term - _monster crush_ on Sans for a while now. You were convinced he'd found out and was making fun of you for it.

 

You kinda wanted to cry a little at the thought.

 

Sans knocked on the bathroom door.

 

"? Look I'm sorry. No more bad pick-up lines, I promise. Please don't be mad?"

 

You narrowed your eyes at the door, your embarrassment gone. Oh no. He started this war, you were going to finish it. You got up, unlocked the door, walked past Sans to go sit back on the couch, and turned the television back on.

 

Sans came to join you shortly after, though he was sitting on the opposite end of the couch now instead of right next to you.

 

3:15 P.M.

 

Sans looked uncomfortable. Good.

 

Time to begin _your_ onslaught.

 

"Hey. Sans."

 

He jumped slightly at your voice.

 

"Y-yes?"

 

"I lost my number, can I borrow yours?"

 

Now he's the one looking confused.

 

"Are you tired? Because you've been running through my mind all day."

 

A tinge of blue covered his cheek bones.

 

"If I could rearrange the alphabet in any order I would put U and I first."

 

More blue.

 

"You've got something on your face." You scooch closer, put your hand on one of his cheeks, and rub your thumb on it. "Oh wait, that's just a smudge of cuteness."

 

You removed your hand. Sans looked very confused by this point. Time to pull out one you knew he'd appreciate.

 

"Are you copper and tellurium? Because you're really CuTe."

 

***Sans has retreated into the safety of his turtleneck.**

 

You laughed at how precious he looked. Only the top of his skull could be seen from the way he pulled his sweater over his face.

 

"Don't dish out what you can't take, Sansy. I enjoy a good joke as much as the next person, but don't use cheesy pick-up lines to do it next time."

 

You heard muffled word coming from underneath the sweater.

 

"Can't understand you."

 

He poked his head out, the blush was still there, but not as strong as when he retreated.

 

"I said it wasn't a joke. I was actually hitting on you."

 

Oh.

 

"Oh."

 

Well then. This is news.

 

4:23 P.M.

 

You two were very uncomfortable right now. You hadn't said anything other than 'oh' at Sans' confession. And was trying not to look at you in shame.

 

_'Of course she wouldn't feel the same, you idiot! She's probably got some human boyfriend that she can live a happy, normal life with!'_

 

Sans didn't like to be left alone with his thoughts.

 

Your thoughts were a bit similar.

 

_'You idiot! Why didn't you say that you were hitting on him, too?! Now he probably thinks you're not interested!'_

 

You looked over at Sans. He looked miserable.

 

"Sans?"

 

He shifted his eyes to you for a brief second before looking back at the TV and giving a small grunt of acknowledgement.

 

"Can- Can I take you on a fig?"

 

You paused and waited for him to look over at you.

 

"What?"

 

"Or would you rather I call it a date?"

 

It took a moment for Sans to get what you were asking.

 

"You- You're serious?"

 

"Yeah. I wouldn't  joke about something as serious as this."

 

Sans could feel that your intent was sincere.

 

He smiled shyly at you.

 

"I'd love to."

 

"Good!"

 

"Great."

 

"Super."

 

"Awesome."

 

"Fantastic!"

 

"Superb."

 

You paused for a second until you thought of the perfect word.

 

" _Sans_ ational."

 

Sans nearly chocked on air.

 

"I can tell that this is the start of something wonderful, .

 

You couldn't agree more.

**Notes for the Chapter:**

> Fluff. So much fluff.
> 
> I love fluff.
> 
> P.S. I tried the insert image thing, but it only does it with the story, I'm trying to get it to show up in just the notes. Anyone know how to do that?


	4. Returning Home

**Summary for the Chapter:**

> Reuploading this because not all of it made it into the previous chapter I wrote.

It was late.

 

Like. _Really_ late.

 

You entered your apartment that you shared with your boyfriend as quietly as you could. You were just getting back from a week long business trip, and you were exhausted.

 

Sans, your loveable, wonderful Sugar Skull, had been miffed when you told him how long you'd be gone for.

 

_"I just don't see why they can't get someone else to go."_

 

_He crossed his arms and pouted on the bed. Oh your baby was just too cute sometimes._

 

_You sidled up next to him and hugged around his middle. He moved his arms and held you tight._

 

_"Baby, this is a great opportunity for me! I don't like that I'll have to be away from you for so long, but don't you want me to succeed?"_

 

_That always got him. He knew how much you loved your job and wanted to excel._

 

_He huffed._

 

_"Yeah, I do. Don't mean I gotta like it when you leave."_

 

_He kissed the top of your head._

 

_"I know, Sans. And as much as I'd like to stay here in your arms, I've got a flight to catch. I'll be sure to call or text you everyday."_

 

_You kissed him on the lips and left for the airport._

 

Now you were home and doing your best to keep quiet. You knew Sans never got enough sleep, so you didn't want to deprive him of even more of it.

 

You tiptoed to your room and began taking off your suit. You refused to wear skirts more often than not because pants were more comfortable.

 

You had stripped down to your underwear when two big, strong arms wrapped around you.

 

Sans was awake.

 

He kissed your exposed shoulders tenderly.

 

"Missed you."

 

You turned around in his hold and kissed him on the mouth.

 

"Missed you too, Sugar Skull."

 

Sans was glad you were home. The past week his sleep schedule had been Hell. He was sure it showed.

 

"Shouldn't you be asleep?"

 

Busted.

 

"Heh. You know me. Always sleep better with you in my arms."

 

You frowned. Sensing your growing disgruntlement, Sans let you go and got you a set of pajamas. An old shirt of his that was baggy and loose on you and a pair of sleep shorts.

 

You thanked him and removed your bra. Sans watched your boobs with great interest until you pulled the shirt on.

 

After getting your shorts on you crawled under the covers and told Sans to join you.

 

"Now you'll get a decent night's sleep."

 

Sans wrapped his arms around you once he was in bed. He kissed your lips and neck.

 

"Hate it when you leave, Babygirl."

 

You kiss his forehead.

 

"I hate it too. But you know I love my job."

 

Sans buried his face into your shoulder.

 

"I love you more though. And good news! Thanks to how well I made the deal go, my boss is giving me the next few days off! We can do whatever you want."

 

" _Whatever_ I want?"

 

"Except dunk on Mettaton."

 

Sans snapped his phalanges in mock disappointment. You giggled.

 

"Get some sleep baby."

 

He turned you over to assume to position of the big spoon. You kissed the hand close to your face.

 

It was good to be home.

**Notes for the Chapter:**

> 


	5. He Ignores You

**Summary for the Chapter:**

> Anony-mouse asked for a touch of angst.

**Notes for the Chapter:**

> I'm not sure where my skill at writing angst falls. I'll do my best.

You wondered if you had done something wrong.

 

Did you say or do anything that would cause your boyfriend to start blowing you off on date night?

 

These were just a few of the questions you've been repeating to yourself for the past three months. At first, you hadn't really minded. You understood that life happened and it would sometimes interfere with your plans.

 

But Sans had stopped just casually hanging out with you, too.

 

So, here you were. Your head in Undyne's lap, crying your eyes out.

 

"I- I- I- I j-just d-d-don't kn-kno-o-ow whatI did wro-o-o-ong!"

 

Undyne was in a bit of a bind. She was a warrior not some sissy! But you were one of her best friends. You'd been there for her whenever she needed you.

 

She'd comfort you for as long as you needed her to.

 

"I'm sure you didn't do anything wrong, ! If anything, HE'S the one who's doing something wrong! Blowing off hanging out with his girlfriend, WHO DOES THAT?!"

 

You sniffled. Sans did. Does. Is. Doing that.

 

You had had tonight planned for months in advance.

 

It was your two year anniversary. That may not seem like a long time to most, but most weren't you and Sans.

 

You stopped sobbing uncontrollably, but the tears still flowed. You were convinced that you had done something to upset Sans and he was giving you the cold shoulder as punishment.

 

Your heart hurt.

 

Undyne was feeling conflicted. You and Sans were her good friends and she cared about both of you. But you were obviously in agony over Sans ignoring you. Undyne made up her mind.

 

She was going to find Sans and force him to explain why he kept ditching you. You didn't deserve to be ditched!

 

You were _not_ Jerry.

 

"Yo, Punk. I'm gonna go get you some ice cream from the store. I'm out. When I get back you are going to eat your feeling and watch anime with me."

 

Undyne left you underneath a blanket. You looked so pathetically heartbroken.

 

Undyne texted Papyrus, asking where Sans was. He said that his brother was most likely at Grillby's.

 

Of course. Where else?

 

Undyne was a woman on a mission. And you don't get in the way of a woman on a mission.

 

Who also happens to be on a motorcycle her girlfriend tricked out for her.

 

_Ever._

 

After running several red lights and ignoring the speed limit, Undyne parked outside of Grillby's.

 

The door swung open heavily and she scanned the pub.

 

There he was.

 

Sans was sitting at the bar and seemed to be chatting with someone. Undyne couldn't see who due to Greater Dog blocking her limited field of vision. Finally, he moved.

 

_It was a woman._

 

Sans had been blowing you off to meet with some other girl! Undyne could feel her magic boiling. Before she completely lost her cool, she looked at the woman a bit closer.

 

She was human. Her hair was done up elegantly and her dress was far too short to be appropriate. Her face was slathered with so much makeup it practically screamed desperate. Yet something was oddly familiar about this woman.

 

Then it hit Undyne.

 

That was your coworker, Becca!

 

You worked in a little dinner on Mainstreet. If you were too busy to take your friends orders - they all visited you at work for lunch sometimes - then Becca would do it.

 

Once when Undyne had visited with Sans and Papyrus, you had been in the back helping the cooks out. Becca came up to the table.

 

She greeted her and Papyrus in an obviously fake friendly way.

 

_But she had batted her eyes at Sans and giggled as she walked away with the orders._

 

Fucking homewrecker!

 

You would always kiss Sans goodbye on his way out, whether you took his order or not.

 

Undyne remembered Becca snapping her pen in anger when she saw you do that.

 

That hussy was trying to steal Sans away from you!

 

Without thinking, Undyne walked briskly to the bar. She cleared her throat and Sans and Becca looked her way. She turned her gaze on Sans.

 

"What are you dong here?"

 

He looked confused.

 

"Uh, nice to see you too? And what do you mean what am I doing here? Just hanging out with a friend."

 

Becca smiled.

 

"Yep. Just me and Sansy spending some quality _alone_ time together!"

 

Undyne's frown got deeper.

 

"On yours' and 's anniversary."

 

Sans looked confused for a moment before his pupils shrunk drastically.

 

But Undyne didn't let him speak.

 

"And on every date night the two of you were supposed to have as well as your hang out days for the past. _Three. **MONTHS.**_ "

 

Becca looked at Undyne a bit fearfully.

 

"W-well, it's not his fault that he wants to spend time with me more than he does her. It's hers! She should try and be a better girlfriend!"

 

Sans snapped his head towards Becca.

 

"You were the one that told me that  called and said that something had come up. You- You're trying to sabotage my relationship!"

 

Becca was stammering.

 

"That's- I- No- It's just- Okay, fine! Yes. I am! She doesn't deserve you! She's a meek little wallflower! You need a woman that is sociable and fun to be around!" She placed her hand on Sans' arm. " _I_ can be that woman, Sansy~."

 

Sans shrugged her hand off in disgust.

 

"I will _never_ want to be with you. I never want to see or speak with you again."

 

Becca's eyes watered and her bottom lip trembled. She left Grillby's with mascara running down her face.

 

Sans sighed.

 

"Where is she, Undyne?"

 

"At my place. You had better fucking apologize like there's no tomorrow and treat her like a goddamn _queen."_

 

The ride back was spent with Undyne explaining how you were to Sans. Once the duo arrived at Undyne's house, the fish woman let Sans in and pointed to where his girlfriend lay sadly on the couch.

 

"Don't fuck this up."

 

You heard footsteps approaching hesitantly. You looked up and saw the nervous face of your boyfriend.

 

"Hey, Babycakes... Mind if I sit next to you?"

 

You shrugged. If he was going to break up with you, might as well get it over with.

 

You had no more tears to cry.

 

You sat up to allow Sans some space. He sat right next to you and pulled you into a strong hug.

 

What?

 

Sans began crying.

 

Sans _never_ cries.

 

"I'm so sorry Babycakes! I didn't mean to ignore you! I had no idea I was even doing it!"

 

Sans explained what Becca had done. You were angry with your coworker for making an attempt on your boyfriend. How dare she!

 

"I should have called to confirm with you. But I had no idea that Becca wasn't a friend of yours."

 

Becca was a notorious liar. She liked to sabotage the relationships of the rest of your coworkers all the time. She'd date the male coworkers after getting their girlfriends to break up with them and date the female coworkers boyfriends once she had split them up as well.

 

"Not your fault... Should've warned you about her. Sorry..."

 

Sans brought your face up to meet his and kissed you softly.

 

"No. No need to apologize. I'm the one who's saying sorry. You did nothing wrong."

 

The rest of the evening was spent with the two of you watching anime with Undyne and catching up on things.

 

You still felt a little sad, but you would get better.

 

Sans would always be there for you.

**Notes for the Chapter:**

>  
> 
> I tried.


	6. Swaplust

**Summary for the Chapter:**

> Swaplust Sans wants his human friend to understand the way he feels.

**Notes for the Chapter:**

> I looked at the reference for Swaplust Sans.
> 
> I think I'll be able to write something decent.
> 
> I hope.

You had just been laying on the living room sofa in the skelebros house when you were pinned down by a tackle hug that had knocked the wind right out of you.

 

"Ooof!"

 

"! I've missed you so much!"

 

Oh. It was just Sans. Sweet, lovable, precious Sans.

 

You struggled to regain the air you lost. Once you had it, you sat up with Sans now sitting comfortably in your lap.

 

You were a good foot taller than him, so it wasn't all that difficult.

 

"Hey, Sans! How was training with Alphys?"

 

Sans turned around in your lap. His little, purple heart eyes glistened with excitement!

 

"It went really well! But we had to cut it short because Alphys had a date with Undyne later and she didn't want to show up late!"

 

You smiled down sweetly at Sans. He felt his soul skip a beat.

 

You had moved in with Sans and his brother about a year and a half ago in response to a 'Roommate Wanted!' ad in the local paper.

 

Papyrus had been seemingly indifferent towards you at the start - secretly he had been surveillng your every move for any sign that you were a threat - but he had warmed up to you in time. He was a pretty cool dude, but flirted shamelessly with everyone like there was no tomorrow.

 

Sans had immediately taken a shine to you, though. He proclaimed that you and him were now 'the greatest best friends in the history of best friends!' after about an hour of knowing him. You didn't mind being the best friend of such a sweetheart.

 

But lately, something had seemed off about Sans.

 

You'd often catch him seemingly staring at you, but it was in that 'lost in thought' way that people sometimes got and unknowingly stared at others with. Whenever you'd snap him out of it, he'd blush bright purple and stammer his way out of the room.

 

You were concerned and asked if anything was bothering him. But he just laughed it off in a completely fake and uncomfortable way.

 

He'd gotten better over the past month, but you were still worried about him. That wasn't the only thing you were worried about though.

 

A month ago, you noticed that your favorite pair of panties had gone missing. You looked everywhere for them, but to no avail.

 

You wondered if anybody from the party the bros had last month went into the laundry room - for whatever reason - and decided to take them.

 

They were a really good pair, too! They were made from silk and were a deep, purple. You'd thrown them into the pile of clothing that needed to be watched due to the, _staining,_ on them.

 

...

 

What?

 

...

 

...

 

...

 

Okay fine! You had creamed in them, cleaned them of all traces of cum - minus the wet patch that was left behind - and threw them in with the dirty stuff!

 

Sans had been watching you for a bit now without even realizing it.

 

You were so beautiful. Your hair was smooth and shiny. Your skin was smooth, too! He loved to touch it whenever he could. Your eyes sparkled like precious jewels. Your laugh - though you said you hated it - was precious. _Especially_ when you snorted.

 

And your lips...

 

Oh your lips looked so soft. Sans often wondered if they would feel as soft as they looked. He'd love to feel them with his fingers, his mouth...

 

_His cock._

 

Sans knew you were still worried about his odd behavior. He was concerned too.

 

_How do you tell someone you love them?_

 

He hadn't expected to feel this way about you. He was perfectly content with just being friends up until a few months ago.

 

You'd had a date with your now ex-boyfriend that night. Sans had helped you pick out your outfit and did your makeup. He knew about such things because he would often help Alphys - who was not a very feminine woman - with her makeup and date outfits for her evenings spent with Undyne.

 

It had only been a half hour since you had left for your date when you came through the front door crying your eyes out. You ran upstairs to your bedroom slammed the door and bawled your heart out on your bed.

 

Sans had heard your door slam and went to check on you. He heard your sobs and hesitantly opened the door.

 

_"Hey, ... Can I come in?"_

 

You sniffled out a yes and Sans plopped down next to you and rubbed your back comfortingly.

 

You had arrived at your scheduled meeting place or your date, only to find your boyfriend kissing some other woman. He tried to lie his way out. Said that he only thought of that woman as a friend and she was trying to force herself on him.

 

You knew he was lying. His nostrils always flared when he lied.

 

You slapped him across the face screaming how you couldn't believe he would just throw away a four year relationship like that. The woman had profusely apologized to you and stated that he had told her he he was single when she met him a month ago.

 

You had actually become good friends with her, but that's another story for another time.

 

You had thrown your arms around Sans crying about how you were going to die alone and unloved.

 

You had looked at him with such sadness that his soul nearly broke.

 

_He realized then and there that he wanted to always see you with a smile on your face._

 

From there, his feelings of protectiveness had grown into desire. Sans wanted you all to himself. You were smart, witty, gorgeous, and kind.

 

Sans loved you.

 

Now, as he sat in your lap thinking indecent thoughts, Sans could feel his pants becoming a bit uncomfortable. He shot up from your lap and up the stairs to his room.

 

"I just remembered something very important that requires my immediate attention! I shall see you at dinnertime!"

 

And then he shut the door.

 

You sat there for a few minutes in confusion. What just happened? One minute you're sitting calmly with your adorable best friend, the next, he's freaking out.

 

_That's **it.**_

 

You didn't care what was so important. Something was clearly bothering Sans, and by God you were going to get answers.

 

You marched up to his door and swung it open, ready to begin ranting when your words died in your throat.

 

You swallowed thickly.

 

Sans was sitting on the edge of his bed, his pants shoved down. He was rubbing a thick, purple cock furiously. He had something held up to his face.

 

Wait...

 

_Your panties! He was_ **_sniffing_ ** _your panties!_

 

"Uh..." Was your response to the imagery before you.

 

Sans snapped his head at the sound of your voice and yelped. He attempted to cover himself.

 

"-! I- I- I can explain!"

 

You shut the door behind you and stalked over to Sans. Sweet, precious Sans.

 

Who was not as innocent as you once thought.

 

"Don't stop."

 

He looked up at you, baffled.

 

"Wh-what?"

 

"I said, 'Don't stop.' Or would you like some help with that?"

 

Truth be told, you had been developing feelings for Sans ever since that nasty break-up with your ex-boyfriend. He was so considerate and fun to be around. He'd always been precious to you, the way he had begun acting after your break-up endeared him to you even more.

 

"H-help?"

 

"Was that a question or an answer?"

 

"I, don't know?"

 

Answer it was then.

 

You stood in front of him and got on your knees.

 

"Want me to suck your cock?"

 

Sans would very much like you to do that yes please.

 

He nodded vigorously.

 

His cheeks were stained a beautiful shade of purple.

 

You licked the head tentatively. Sans moaned at the contact. You repeated the action several times, eliciting the same response.

 

You licked up and down the length of his shaft. You gripped the base and moved your hand in small semi-circles.

 

Sans bit down on his phalanges. You were really good at this.

 

You smirked and began nipping at his dick. You kissed each place after you bit at it. You reached up and pulled Sans' hand out of his mouth.

 

"Don't hide those cute little noises from me, Sweetie."

 

You didn't give him a chance to respond before you wrapped your lips around the head of his cock and _sucked._

 

Sans let out a high pitched squeal. Never in his wildest dreams did he imagine your mouth would feel this good.

 

You'd _ruined_ everyone else for him.

 

And Sans was okay with that.

 

You moved your mouth down Sans' penis and put as much of it in there as you could. What you couldn't fit in your mouth, you pumped with your hand.

 

You began bobbing up and down on Sans at a slow pace. He whined like a bitch in heat. That sent a small surge of heat to your core. You undid your shorts and shoved the hand not on Sans' cock down your underwear. You began rubbing small circles on your clit with your middle finger.

 

"Mmmmmm~." You moaned around the cock in your mouth.

 

"Ah! -! Y-you feel s-so good!"

 

Sans grabbed the back of your head and moved you up and down on him at a faster pace. Not fast enough to gag you though.

 

You inserted two fingers into your sopping entrance and began pumping them in and out. to the rhythm of the pace Sans set.

 

You tightened the hand on Sans a bit and circled the head of his dick with your tongue before going back to sucking.

 

Sans was close. He could feel that little coil getting tighter and tighter. If you kept going the way you were, he'd come in your mouth and down your throat. He knew he should stop you but...

 

You felt too good.

 

"Ah! , ! I- I'm close! I'm-! I'm gonna-!"

 

Sans came with a violent shudder and a shout. You swallowed as much of his cum as you could, though some did seep out the sides of your mouth. The flavor reminded you of grape jelly.

 

You felt your fingers. Slick with your cum.

 

It took a minute or so for Sans to get his breathing under control. Once he did, you got on the bed and held your slick fingers to him.

 

"Here, I tasted your cum. Now you taste mine."

 

Sans blushed. He had no idea how lewd of a person you really were. Though, he was no better. He knew everyone thought he was an innocent little baby.

 

Sans took your fingers into his mouth and lapped your juices off of them. He couldn't place what you tasted like, but it was definitely something sweet.

 

The two of you sat there in silence.

 

"So," Sans started, "Do you maybe, wanna, I don't know-"

 

You placed your finger on his mouth.

 

"The new Ghostbusters is out. We can go see that this weekend."

 

Sans grinned and clung to you tightly.

 

"I promise this'll be the greatest date you've ever been on!"

 

You knew that he'd keep that promise.

 

 

 

 

**Notes for the Chapter:**

> I hope I was able to capture Swaplust Sans' personality. And if I didn't...


	7. No Control

**Summary for the Chapter:**

> Sans tries his best to be gentle with you, but ultimately fails.

**Notes for the Chapter:**

> I think I'm just going to write five more chapters. I may do another prompt fic later on, but I think having ten chapters (not counting the first one because it's an introduction) for my first prompt fic is a good way to start.
> 
> So, we're in the home stretch of this story being over.

_He's shaking._

 

You and Sans had been together for a few years now. The two of you were no strangers to intimacy with each other.

 

But tonight was different somehow.

 

It had started off like it usually did. The two of you were just relaxing in your shared bedroom, exchanging a few kisses here and there before Sans turned up the heat.

 

He gently pushed you down onto the bed and began to kiss you with a feverish passion. He nipped and licked at your lips before plunging his tongue into your mouth.

 

There wasn't much of a fight for dominance. Sans' magic tongue always left you with a buzzing feeling in your mouth that sort of subdued you a bit. Not that you minded it in the slightest.

 

Sans had clawed at your shirt and pants inn an effort to get them off. You sat up and helped him with the task of getting you naked. He practically ripped off your bra and underwear before latching his mouth onto one of your erect nipples. He pinched and rolled the other one between his phalanges.

 

"A-ah!"

 

Sans loved how you tried to make yourself be quiet. You always failed, and he took immense satisfaction in knowing that he made you lose your composure.

 

He flicked the nipple in his mouth with his tongue and lightly nipped at it.

 

"Mmmph!"

 

You were biting your knuckles in an attempt to muffle yourself. Normally Sans would wait for you to make yourself louder, but he was impatient tonight.

 

He grabbed you by the wrist and roughly pinned your hand to the bed.

 

" **Don't.** Not tonight, Doll. I wanna hear you _fucking cry out_ while I pleasure you."

 

Sans was practically growling. This was new.

 

Sans removed his hoodie and shoved off his pants. Your sight was greeted with a familiar blue cock. Your mouth watered a bit at the sight. Oh the things Sans could and did do to you with his magic-!

 

You could feel your already dripping entrance get even wetter.

 

Sans grabbed you by the thighs and shoved your legs up to your chest.

 

"Hold your legs here while I enter you."

 

His cold demeanor tonight was a drastic change from his usually playful self. But you did as you were instructed.

 

This side of Sans was really turning you on.

 

Sans grabbed his cock and lined himself up with your sopping cunt. He could _smell_ your arousal.

 

He pushed into you slowly and gently. You had stated after the first few times the two of you had sex that you weren't a big fan of rough play. Sans couldn't say that he wasn't a little disappointed when he heard that.

 

Once he was fully immersed in you he stayed still. Even after all the 'fun' times you two have had together, you still needed a bit of time to adjust to Sans' size.

 

"F-fuck, Doll! I still can't believe you're this tight~!"

 

Your breathing was beginning to get heavy. Sans was always gentle with you, but he still made you breathless and a bit sore after the fact.

 

He began pumping in and out of you at a slow, easy pace. How he knew you liked it.

 

But Sans was impatient tonight.

 

There was nothing more that he would like to do than flip you over on your hands and knees and pound mercilessly into you from behind. Just the thought of doing it made his cock throb with want and expand a bit.

 

You could've sworn you felt Sans grown a little bit inside you. Must be your imagination.

 

Sans groaned out in pleasure and frustration. You felt even tighter with his new size and that was a bit of a problem.

 

_Sans was getting desperate now._

 

Without warning, he picked up the pace.

 

"Ahn! S-Sans! Fuck, baby! A little- A little warning next time, yeah?"

 

Sans stopped listening after you cried out. You refrained as best you could from cursing in bed. To hear you lose it for a moment there...

 

_It turned him on so much fucking more than he already was._

 

Sans lowered his face to yours and gave you this needy look.

 

"Ngh! Babydoll, please, please, _please!_ Let me- ah fuck! Let me be rough with you! Let me fuck you hard! God, Doll, please! I need this I need this I need this!"

 

Sans had stopped moving save for rotating his cock clockwise inside you.

 

You looked Sans in the eyes.

 

God he was a mess. He was drooling, his blazing iris' pupil had taken on the shape of a heart, and his entire face was flushed blue.

 

How could you say no to him?

 

"Just, if I want you to stop, you _stop._ Okay?"

 

Sans looked like he was about to sob tears of joy.

 

"Thankyouthankyouthankyou! I promise you'll enjoy it baby, I promise!"

 

Then he promptly pulled out of you, flipped you over, had you sit up on your hands and knees, and delved back into you swiftly.

 

"A-a-ah!"

 

It didn't hurt all that much, but you had no time to think before Sans began pounding into you without missing a beat.

 

"D-damn it-! Ah! S-sorry for cursing. Mmmmn!"

 

Sans draped himself over you as he picked up the pace.

 

"Don't be, baby. _Fucking_ swear all you want to! It's just us here."

 

Sans placed kisses on your back and neck. God you were just amazing! He'd never understand just how he managed to be so lucky to have you in his life.

 

_He's shaking._

 

Sans was visibly trembling and switching between whimpering praises and growling out all the lewd things he wanted to do to your body into your ear. He licked the outer shell before biting a trail down your neck.

 

He'd never _bitten_ you before. It was always little nips that he would suck or lick on as soon as he inflicted them.

 

You _liked it_ when Sans bit you.

 

Sans was close. He could feel your inner walls constricting and knew you were too.

 

He shoved you onto your side, ignoring your yelp of surprise. Hi hoisted your leg over your shoulder and began pounding into you harder than he had been.

 

The result was instantaneous. You were writhing and thrashing in ecstasy. Sans hit your cervix and you saw white.

 

Sans came hard and fast with you when your walls clamped down almost painfully on his cock.

 

"FUCK, BABYDOLL!"

 

Sans didn't care if anyone had heard him. You were still cumming. You kept clenching down on him as you experienced a few little aftershocks of pleasure.

 

You finally stopped and Sans pulled out.

 

Oh God, you were leaking cum all over the bed.

 

Sans felt his magic flare in response to the sight. But now wasn't the time.

 

You couldn't move. You felt boneless.

 

Sans went into the bathroom that was connected to your bedroom and began running a warm bath for you. Once the water was warm, Sans plugged the drain and went back to the bed. He picked you up and set you down in the rising water.

 

Sans got into the tub with you and began cleaning the two of you up.

 

"You did so good, baby. So good. Thank you for letting me do that. I love you."

 

You smiled weakly at Sans. That had taken a lot out of you.

 

"Love you too, Sans. I probably won't want to do that again, at least, not something that intense. You really like giving it rough, huh?"

 

Sans ducked his head in embarrassment. You laughed a bit.

 

"No need to be embarrassed. We can try small rough things. I've seen your browsing history. Also, I found out that I like it when you bite me."

 

Sans looked up at your mention of trying things out and flushed spectacularly when you mentioned the biting.

 

The marks were prominent and wouldn't be fading for a while. The one at the base of your neck was bleeding a little.

 

"Shit! I'm so sorry, baby! I didn't mean to draw blood!"

 

"It's okay. You'll just have to be more careful next time."

 

"Sure! Of course! Definit- Next time?"

 

You smiled.

 

"Next time."

 

Sans smiled back.

**Notes for the Chapter:**

> 


	8. Monster Girl

**Summary for the Chapter:**

> You are a skeleton monster. You've lived as far from other monsters as possible up until a few years ago, when you moved to Snowdin. You got close with everyone, even the bros.
> 
> Lately, Sans has been doing some pretty odd things.

**Notes for the Chapter:**

> You're shorter than Papyrus but a little taller than Sans.

You could see your breath as you walked through Snowdin's forest. You often took walks out here when something was troubling you and you needed to think about it.

 

'It' being how Sans had been acting odd as of late.

 

You moved to Snowdin about five years ago when you had turned eighteen.

 

Your parents had always lived as far away as possible from other monsters. Skeleton monsters were known to be private, mostly, but your parents took it to a whole new level. You never had friends growing up so coming out this far away from New Home and meeting all sorts of nice people was a much welcomed change.

 

You lived on the north side of town near the nice family of rock monsters. You have a bad habit of not answering the door whenever someone has a particularly pleasant knock.

 

...let the record show you're a bit of an oddball.

 

Back to your backstory.

 

When you first moved here, you met the rabbit sisters. The shopkeeper, Lillian. And the innkeeper, Fern. They were the first friends you ever made.

 

After a few months of you living in Snowdin was when _they_ came along. Sans and Papyrus. You had never met any other skeleton monsters other than your parents, so it was jostling to see two others.

 

By that point you had gotten to know everyone in town. You weren't exactly sure how to approach the newcomers. You had always been introduced to new people by your other friends.

 

With the brothers, it was no different.

 

You had woken up to frantic knocking at your door in the middle of the night.

 

It was Swirls, the rabbit that frequented Grillby's.

 

With her were Sans and Papyrus.

 

"This is ," Swirls stated, for once not tipsy out of her gourd.

 

Papyrus looked ecstatic to meet another skeleton monster and said just that. Sans...

 

Sans was Sans. That should suffice as an explanation.

 

From that point on Papyrus made certain to invite you over for dinner every night. While the gesture was sweet, you had started taking more hours at Grillby's to avoid Papyrus' spaghetti.

 

It was really bad.

 

But you hung out with him and Sans on a regular basis. Those two were your closest friends now.

 

Lately though, Sans had been acting... Odd, for lack of a better term.

 

It had started a few months back. Whenever Papyrus had to go out on patrol, leaving just you and Sans in the house, Sans would - for whatever reason - build some sort of nest out of blankets and pillows on the couch and sit in the middle of it. He'd just give you this look whenever he did and you would stay a respectful distance away from his nest.

 

Other times, he'd come over to your house and leave flowers everywhere. You still hadn't found all of them.

 

If that was his way of trying to brighten up the rooms of your house, then Sans had strange tastes in interior décor.

 

So here you were, out in the woods, pondering on your dear friends quirky behavior as of late.

 

You hadn't been paying attention to where you were walking, and failed to notice the sentry station with the subject of your thoughts in it.

 

Sans watched you unknowingly walk towards him. You looked lost in thought. He knew you had picked up on his behavior.

 

What he didn't know was why you had yet to do anything about it.

 

You two had been friends for years. Sans had developed feelings for you three years ago and was only acting on them now.

 

He was sure he was doing everything right. His instincts told him so. The pillow and blanket nests he kept making were to symbolize to you that he was a good provider. The flowers symbolized that he would love and care for you until his dying day.

 

So why weren't you responding? He could understand if you weren't interested, but you hadn't said anything accepting of or rejecting his courtship.

 

You heard someone clear their throat to your right.

 

"Hey."

 

Oh. It's Sans.

 

"Hi Sans."

 

"What brings you all the way out in my _neck of the woods?_ "

 

Ha.

 

"Just thinking."

 

"About?"

 

You went through your options. 1. Answer honestly. 2. Dodge the question.

 

Number one.

 

"You actually."

 

Sans felt his breath hitch.

 

"R-really?"

 

You nodded.

 

"Yeah. You've been acting pretty weird lately. Is everything alright?"

 

"Weird how?"

 

"Well... You build pillow and blanket nests whenever I come over and you keep leaving flowers all over my house when you visit. So, I reiterate, is everything alright?"

 

Sans could only look at you disbelievingly. How could you possibly not know about the courtship habits of monsters! You'd have had to live far away from everyone- Waaaaaaaaaaait. You had lived far away from everyone growing up. Shit.

 

No wonder you had no idea about this. Your parents hadn't seen a need to explain it because, as you once said in passing, they thought you'd just stay at home forever. You'd never had friends growing up so you had never been privy to anyone attempting to court or being courted by anyone.

 

Double shit.

 

Now you were looking at him in concern.

 

"Yeah! Everything's just... Great!"

 

Sans was screaming on the inside. Loudly. In frustration.

 

**_One month later..._ **

 

Sans was not great.

 

At all.

 

For the past month Sans had been trying to subtly explain to you the courtship process.

 

With absolutely no luck whatsoever.

 

God you were like his bro with your naivety sometimes.

 

That only made you all the more precious to him.

 

You were both sitting on the couch watching one of Mettaton's many shows. Sans was doing his best to refrain from building another nest.

 

Meanwhile, you were freaking out inside.

 

Undyne, one of your other close friends, had unwittingly explained Sans' strange behavior.

 

You had been visiting her with Alphys when she began building her own coach nest.

 

Alphys sputtered and became a blushing mess.

 

"Hey, Sans keeps doing that too. What does it mean?"

 

They gave you this 'you serious?' look. Before Undyne dove headfirst into the explanation of courtship.

 

You were utterly embarrassed when you found out, to say the least.

 

Undyne proceeded to tease you mercilessly about it.

 

"Ha! Now you know he likes you the way you like him, NERD! All you have to do is build him a nest or whatever!"

 

Now here you were. On the bros' couch once more. Sans looked very uncomfortable.

 

Sans got up saying he was going to make popcorn.

 

Now was the time.

 

You worked fast, but not sloppy. Blankets draped over the couch, manipulated to look like a large bowl lined with pillows.

 

You were sitting in the middle of it when Sans came back into the room.

 

He nearly tripped over his feet when he saw you sitting in your nest.

 

"Uh..."

 

"So Undyne explained the whole 'courtship' thing to me. To be honest, I'm glad she did. I had no idea how to tell you how I felt. Also, I was very embarrassed when she told me. Here you were courting me for a while, and I had no idea what you were doing!"

 

Sans could feel the blushing.

 

But that wasn't a bad thing. Your actions and words vanquished any fears about you not feeling the same.

 

Sans tried not to appear to eager when he made his way to join you in the nest. He snuggled up next to you.

 

This was nice.


	9. Surprise

**Summary for the Chapter:**

> Reader has some exciting news to share.

Your hands were shaking frantically. You couldn't believe your eyes.

 

Positive.

 

Your pregnancy test was positive.

 

You were glad no one else was home to hear you squeal like a madwoman.

 

You and your husband Sans had been trying for a year to get you pregnant. Thanks to your cousin for getting his monster girlfriend pregnant, you had been enlightened that it was a very real possibility.

 

Phone in hand, you were about to call Sans when an idea struck you.

 

Why not surprise him with the news?

 

Your birthday was next month, all your friends and family would be in one place.

 

It was perfect.

 

But you had no idea what to do for it! You decided you'd let one of your friends in on the surprise so they could help out. But who to tell?

 

Not Papyrus. Sweet cinnamon roll couldn't lie to save his life. Alphys? Nah, she'd get too nervous and unintentionally spoil the surprise. Toriel? No. You had a feeling Frisk would be listening in on the conversation and tell everyone. Not Asgore. He's busy enough. Mettaton?

 

NO. Just. No.

 

That left one other person. You dialed her number.

 

To say Undyne was excited would be an understatement. She fucking _ran_ all the way to your house, kicked the door in, and yelled 'LET'S START THINKING OF THINGS TO DO!'

 

You weren't the least bit surprised by her reaction.

 

The two of you went through ideas in your heads. Neither of you thought they were any good. Undyne stated that the internet would probably have something good.

 

You searched through several sites until you found one you were completely on board with.

 

"Oh my God we are so doing this one."

 

Undyne looked at it and began cackling.

 

"Good one, Punk! They won't see it coming!"

 

_**One month later...** _

 

You were excited and nervous all at the same time.

 

Today was your birthday. Today, you'd break the news to everyone.

 

Undyne gave you a thumbs up. She had everything set up.

 

You went to go find Sans. He was on the couch watching a documentary about human births.

 

How fitting.

 

"Hey Sugar Skull," you crooned and sat beside him. He smiled and kissed you sweetly.

 

"Hey, Babycakes. Happy birthday."

 

"Thank you, Sans. Hey, can you help me bring everyone into the kitchen? I wanna take a group photo."

 

"Sure thing, Baby."

 

You and Sans rounded everyone into the kitchen.

 

"Okay, I want you all to scooch in close together. Undyne, you got the camera ready?"

 

She nodded in affirmative. She was really trying not to laugh.

 

She set the timer and you two got into position.

 

"Okay pinks, everyone say 's pregnant!"

 

"'s PREGNANT! WAIT WHT?!"

 

The flash went off and captured everyone's shocked expressions. You and Undyne were the only two laughing.

 

Everyone surrounded you and gave their congratulations.

 

But no one was more elated than Sans. After everyone had headed home, he lifted you up and spun you around before dipping you and kissing you deeply and passionately.

 

"You have no idea how happy I am, Babe."

 

"I think I have an idea. Bet you can't wait to be a daddy."

 

His grin grew even wider.

 

"Nope!" He lowered his head to your belly. "Can't wait to meet you kiddo." He lifted your shirt a bit and kissed your stomach. "I promise to be the best dad you could ever have."

 

You both went to sleep very happy that night. You whispered to your belly just before you fell asleep.

 

"Goodnight, Sweetie. I can't wait to show you the world."

 

 

 


	10. Beg For It

**Notes for the Chapter:**

> [Here's a link to my tumblr if you wanna talk or ask questions](https://sharkdukes.tumblr.com/)
> 
>  
> 
> Fair warning, you may think the few things I've liked and reblogged are weird.

He was so cute like this.

 

A tied up, blushing _wreck._

 

You smirked to yourself as you raked your eyes over your trussed up boyfriend.

 

To think this all started because Sans was convinced you couldn't make him beg. Turn him into a horny, growling mess? Sure. But begging?

 

You 'didn't have it in you,' according to him.

 

He had no trouble humoring you though. He thought that you'd straddle him and do your best to try and seduce him, not that you had trouble with that, and attempt to push him over the edge.

 

Oh you straddled him alright.

 

But only to tie him up.

 

Sans, to say the least, was shocked at how good you were at tying knots. You'd been practicing for a while in preparation for this moment.

 

He wouldn't have a problem with getting out. But like you previously stated, he'd humor you.

 

Sans saw your amused smirk and chuckled.

 

"You look like you've got something in mind. Care to share?"

 

Your smirk grew into a devious grin. Oh if only he knew what you had recently discovered about skeleton monsters.

 

Mettaton was a huge gossip and had no problem with helping you find all sorts of ways to rile Sans up.

 

You would never understand the tension between them, other than the fact that Mettaton was dating Papyrus, but were glad that at least _someone_ could tell you about certain places you could touch your boyfriend to make him squirm.

 

"No. I think I'll just do my thing."

 

You had stripped down to your underwear earlier. It was a little chilly in Sans' room, but not unbearably so.

 

Mettaton had told you something _very_ interesting.

 

Skeleton monsters had sensitive bones.

 

That would explain why Sans was usually bundled up and left most of his clothes on during sex.

 

But not tonight.

 

You had his all of his sleep shirts and made him take off the stained one he was wearing. He nervously did so, but soon relaxed. He didn't know you knew.

 

His legs you had left untied to remove his shorts easily.

 

You stalked over to the bed, crawled up between Sans' legs, and gave him a wicked grin.

 

Sans felt his soul hammer in anticipation.

 

He always found everything you did sexy. You may not get him to beg, but you sure would put on one Hell of a show.

 

You had more in mind than just a simple 'show.'

 

You gently placed your hands on his ribcage. Sans' breath hitched a little bit.

 

"You remember the safe word?"

 

He nodded.

 

"Yeah, satin. Don't worry, Baby. I know you'll do your best to not do anything I'd be uncomfortable with."

 

You smiled. He trusted you so much. That was one of the reasons you loved him.

 

You arched your fingers and scraped your nails down his ribs.

 

"F-fuck!"

 

You smirked devilishly down at him. He was already panting. His blush had spread even further along his cheek bones.

 

"H-how-"

 

"You know how much Mettaton loves to gossip."

 

That damn pile of scrap metal.

 

You licked a trail down the length of one of Sans' ribs.

 

God _bless_ that damn pile of scrap metal.

 

Sans struggled against his binds. How were you so good at this?!

 

You nipped and kissed at several of his ribs before moving up to his neck.

 

You sucked and licked at it for a while before you bit down. Hard.

 

"Mmmngh, shit! Fucking-! Hell-!"

 

He was panting hard now. The blush had spread all over his face. You pulled back.

 

"Why'd you- Why'd you- Why'd you stop?"

 

You snickered.

 

"Because you only swear excessively like that for two reasons. One: you're seriously pissed off. Two: you're about to come. You were clearly enjoying yourself, judging from the erection currently poking my abdomen through your shorts."

 

You leaned down to whisper next to his cranium.

 

_"You haven't earned the privilege to come yet."_

 

Sans shivered.

 

He was in deep shit.

 

For the next two hours you teased and tormented Sans mercilessly. You'd brought him close to the edge so many times only to stop your ministrations and waited for him to calm down before resuming. You had only touched his bones, completely ignoring his throbbing member.

 

You'd gotten naked after the first hour to touch yourself while Sans sat there, too far gone to even think about using his magic to break the rope, pin you down, and pound into you until you couldn't remember anything but his name.

 

Enough was enough.

 

"P-please!"

 

You stopped massaging your breasts.

 

"What was that?"

 

"Please!"

 

You crawled back on top of him.

 

"'Please' what?"

 

Sans bit his lip. He could either swallow his pride and let you send him into sheer bliss or be stubborn and let this torture continue.

 

"Please, please, _please_ Baby! I can't- I can't-! I- Please, just fuck me!"

 

You kissed the top of his skull.

 

"Good boy."

 

You swiftly removed his shorts. His cock was weeping, pre-cum smeared all over it. You pumped up and down his shaft a few times to get him properly coated, the positioned yourself over him before slamming down on his cock.

 

"Fuck yes! _Yes!"_

 

Sans was sobbing in relief. You were soaking wet, warm, and tight as always.

 

"Mmmnnn~!"

 

Sans always made you feel good whenever the two of you had sex. He fit snugly inside you and stretched your walls in such a way that it burned in the most pleasurable way.

 

You bounced up and down at a desperate pace. Sans wasn't the only one being tortured for the past two hours. You'd wanted nothing more than for him to screw your brains out from the start.

 

But you had had a point to prove. And you proved it.

 

You leaned down to kiss Sans frantically. Your tongues met in a desperate dance for dominance.

 

You were close, as was Sans.

 

"Baby! Fuck I- I'm-"

 

Sans came harder than he ever had. He could feel your cunt clench, signaling your release. But all he could hear was distant ringing as he came down from his orgasm high.

 

You managed to get the ropes untied before collapsing on top of Sans. He immediately wrapped his arms around you and pulled you both under the covers. He placed lazy kisses allover your face, causing you to giggle. He always got extra clingy after sex.

 

"So, what have we learned?"

 

Sans paused his kissing spree to look you bashfully in the eye.

 

"Don't doubt your ability to make you beg like a bitch in heat?"

 

You smooched his cheek.

 

"Exactly. Told you I could do it."

 

He chuckled and pulled you closer, eyes beginning to feel heavy.

 

"That you did, Babe."

 

He could hear your soft breathing. You were asleep. He kissed the top of your head softly.

 

"That you did."

**Notes for the Chapter:**

> This was fun to write.
> 
> One chapter left to be written.
> 
> P.S. I decided to delete my Underfell story. I may return to it one day, but until then I don't want it just sitting there while people wait for me to update.
> 
> P.S.S. On the other hand, I was thinking about doing a different AU. But I'm not entirely sure which one.
> 
> Also, I don't know if I'll include my trio in it or not.


	11. Pop!

You'd been sitting on the couch for far too long by this point.

 

No really, your back was starting to go numb.

 

But you didn't want to get up. Today was your first day off in _months_ and you wanted to enjoy it by doing absolutely nothing at all. And that's what you had been doing for the past four hours, just watching television and texting your friends.

 

You were beginning to relax again and began to ignore the slightly uncomfortable numbness in your back when someone knocked on the door of your apartment.

 

"Uuuuuuuuuuuuuuuuuuuuuuuugh! Whhhhhhhhhhhhhyyyyyyyyyyyyyyyyyyyyyyyyyyyy?!"

 

You begrudgingly got up, a bit wobbly you had to hold still for a minute. Whoo! Headrush.

 

Your joints are really stiff as you cross the short distance from the couch to the door. You open it.

 

"Oh, hey Sans."

 

Sans. One of your good friends. To be honest, you wouldn't mind being more with him, but as of late - whenever the subject of romance comes up - he's been talking about this lady he's had his eye on for a while.

 

You didn't have a shot and you knew it. But you were happy being his friend.

 

"Hey, . Been enjoying your day off?"

 

"Yeah. _Tibia_ honest, it's been a long time coming. I get that my job is hectic and all and sometimes requires me to drop everything, but I just need a little 'Me' time every now and then, you know?"

 

Sans nodded. He definitely could understand the need to have a day to slack off.

 

You leaned against the doorframe.

 

"So what brings you here?"

 

"Oh! Right." He reached for the backpack he had on. "I came to return your copy of 'Kiki's Delivery Service' that you lent to Papyrus. He really enjoyed it."

 

"Hey thanks dude!" You took the DVD from him. "You wanna come in? Or do you gotta be somewhere?"

 

Sans mulled this over in his head. He wasn't really doing anything of great importance.

 

"Sure. You know how much I _a-door_ our time together," he snickered while knocking slightly.

 

You snirked and moved to the side to let him in.

 

"That was so bad. Seriously, you need new material."

 

Sans plopped down on the couch and focused on the muted television.

 

"Eh. They can't all be winners."

 

You squatted next to the DVD case to put the movie away. As you did, your knees cracked pleasantly.

 

"Ah~! That felt nice."

 

You turned around and Sans was giving you this _look._

 

"What?"

 

"N-nothing. S-so," he cleared his throat. "What're you watching?"

 

You flopped down on the couch next to Sans.

 

"Meh. I haven't really been paying attention. Just flipping and watching stuff that looks interesting enough." You laced your fingers together, stretched your arms out, and popped them. "Mmmm~."

 

Sans shifted uncomfortably. God damn it why did you have to make those noises?!

 

He'd had his eye on you for a while and had been dropping subtle hints here and there.

 

But you just had to be almost as sweet and oblivious as his little brother, didn't you?

 

You heard Sans grunt softly. Was he okay? You glanced over. He was averting his gaze from you quite obviously. He was blushing pretty hard.

 

Why? He didn't seem sick. Oh well.

 

You rolled your wrists around until they cracked.

 

"Ah~!" They didn't really feel stiff, but it felt nice to feel them shift back to their proper place.

 

Sans grunted again, a little louder than before. You looked back over at him, mouth open to ask what was wrong when you saw it.

 

Sans was crossing his legs in a vain attempt to conceal his erection.

 

Oh?

 

You popped your knuckles experimentally and watched as Sans bit his lower lip to muffle himself.

 

_Oh-ho!_

 

"So, Sans. Tell me about this girl you've had your eye on. Is she someone the whole gang knows?"

 

Sans shifted uncomfortably.

 

"Uh, y-yeah. I guess you could say that."

 

You cracked your ankles.

 

Sans flinched.

 

"Oh, sorry dude. My joints are just pretty stiff and hurt a bit. I can stop if it's making you uncomfortable."

 

"NO! I mean, if you're in pain, keep on with what you're doing."

 

You hummed out a thank you.

 

"So what's this girl like?"

 

"She's, well, she's pretty cool, smart, funny, beautif- No. _Stunning._ She laughs at all my jokes even though she says they're pretty terrible. She's one of the kindest people I've had the pleasure of meeting."

 

"Have you told her any of this?"

 

"I just did."

 

You'd had a feeling the girl was you when you noticed how aroused Sans had become. If it wasn't you, he would have just asked you outright to stop.

 

That's how he was with people who did something he was uncomfortable with, or with people that were into him and he just didn't feel the same.

 

But that didn't stop you from blushing somewhat.

 

"O-oh."

 

He shifted closer, his legs spread in a way that showed off the bulge in his shorts.

 

"And I have a feeling she feels the same way."

 

He cupped your cheek and kissed you chastely.

 

"Now. As much as I'd like to stay here and kiss you, I've got a problem that's a little _hard_ to take care of with someone around. So I'll just be- Oof!"

 

You shoved him back on the couch.

 

"I can help you with that." You cracked your neck. "Y'know. If you want me to."

 

"I would very much like that yes."

 

You laughed.

 

And cracked your fingers in preparation of what was to come.

 

Sans shuddered in delighted anticipation.

 

A smirk made its way across your face.

 

"Good. I'll take a _crack_ at it."

 

Sans hadn't thought it possible to be able to fall even more deeply in love with you than he already had.

**Notes for the Chapter:**

> No actual sin.
> 
> BUT IT WAS HEAVILY IMPLIED!
> 
> I wanna thank everyone who sent in their requests! I'm sorry that I didn't get to them all though. :,( Hopefully once I get the hand of what I'm doing I'll start up another prompt fic. Until then I will just update my other fic at my own pace and possibly try writing another one.
> 
> But not the Underfell one.
> 
> That one has been deleted and I don't know if I'll ever bring it out of the box again.
> 
> Or if I do, it probably won't have the same start as the old one did. 
> 
> Probably.


End file.
